A modern air conditioning system can look very discreet inside a room, but the pipework connecting the indoor and outdoor units still needs somewhere to go.
Refrigeration pipes, electrical cables and condensate drainage can all form part of the installation. If these services are left exposed, even a well positioned air conditioning unit can look unfinished.
Air conditioning trunking provides a simple way to cover these services and create a cleaner, more professional appearance.
In this guide, we explain how air conditioning pipework can be hidden, where trunking is normally used, how to plan a discreet pipe route and what to consider before installation begins.
You can also read our Air Conditioning Trunking Buyer’s Guide or browse our air conditioning installation accessories.
How Do You Hide Air Conditioning Pipework?
The most common way to hide visible air conditioning pipework is with purpose designed trunking.
Trunking creates a protective channel around the services running between the indoor air conditioning unit and the outdoor condenser.
Depending on the installation, it can conceal:
- Refrigeration pipework
- Pipe insulation
- Electrical cable
- Communication cable
- Condensate drainage
Rather than seeing several separate pipes and cables running across the wall, you see one neat trunking route.
What Does Air Conditioning Pipework Look Like?
A split air conditioning system normally has refrigeration pipework running between its indoor and outdoor units.
These copper pipes are insulated, so the finished service run is larger than the bare copper pipe itself.
The same route may also include electrical cable and a condensate drain.
Without trunking, you may therefore see several insulated pipes and cables travelling along the outside of the property.
Trunking groups these services together and covers them.
Why Hide Air Conditioning Pipework?
The main reason is appearance, particularly on homes and customer facing commercial properties.
Trunking can also help protect the installation.
Benefits include:
- A cleaner appearance
- Less visible pipework
- Protection for pipe insulation
- Protection for cables
- A more organised service route
- A professional finished installation
- Different colour options to suit the building
If the outdoor condenser is positioned carefully and the pipework is neatly covered, an air conditioning installation can be considerably less noticeable than many homeowners expect.
Can Air Conditioning Pipework Go Straight Through The Wall?
Yes. This is often the neatest arrangement when the indoor unit is mounted on an external wall.
The refrigeration pipework, cable and drainage can pass through the wall directly behind or close to the indoor unit.
On the outside, the services can then enter trunking and travel to the outdoor condenser.
This arrangement can minimise visible pipework inside the room.
However, the final route depends on:
- The position of the indoor unit
- The position of the outdoor condenser
- Building construction
- Drainage requirements
- Pipe length limits
- Access for installation
What If The Indoor Unit Is On An Internal Wall?
An internal wall can make the pipe route more complicated because the services cannot simply pass straight outside.
Instead, the pipework may need to travel:
- Across an internal wall
- Along the top of a wall
- Through a cupboard
- Through a ceiling void
- Through a loft
- To the nearest suitable external wall
Where the services remain visible indoors, trunking can be used to conceal them.
This is one reason it is worth discussing indoor unit positioning before installation begins.
Can Trunking Be Used Indoors?
Yes.
Although many people associate air conditioning trunking with external walls, it can also be used inside the property.
Indoor trunking is particularly useful when:
- The indoor unit is on an internal wall
- The pipe route cannot pass directly outside
- The services need to travel across part of the room
- Pipework runs close to the ceiling
- A visible route needs to be made more discreet
The shorter and simpler the route, the easier it usually is to create a neat result.
Can Trunking Be Used Outside?
Yes. External walls are one of the most common places to see air conditioning trunking.
Once the pipes leave the property, trunking can cover the route between the wall exit and the outdoor unit.
This can include:
- A vertical drop down the wall
- A horizontal run
- A combination of horizontal and vertical sections
- Routes around corners
Purpose designed fittings allow the trunking to follow the shape of the building.
Plan The Outdoor Unit Position First
One of the best ways to minimise visible pipework is to choose the outdoor condenser position carefully.
A condenser positioned close to the indoor unit can potentially reduce the amount of external pipework required.
However, pipe length should not be the only consideration.
The outdoor unit also needs:
- Good airflow
- A secure mounting position
- Suitable clearances
- Access for servicing
- A sensible noise location
- A suitable electrical route
Read our Air Conditioning Brackets & Feet Guide for more help choosing the outdoor unit position.
Keep The Pipe Route As Simple As Possible
A simple pipe route is usually easier to conceal than one with many bends and changes in direction.
Where possible, aim for:
- Short straight sections
- Clean vertical drops
- Clean horizontal runs
- Minimal unnecessary bends
- A direct route to the outdoor unit
This can improve both appearance and installation simplicity.
The final route must still follow the requirements of the air conditioning system and building.
Use Corners And Fittings For A Cleaner Finish
Air conditioning trunking systems normally include fittings that allow the cover to follow the building neatly.
Depending on the installation, these may include:
- Internal corners
- External corners
- Flat bends
- Connectors
- Wall covers
- End sections
Using the correct fittings produces a much cleaner result than simply joining straight lengths together around a corner.
Should Trunking Run Vertically Or Horizontally?
It can run in either direction.
The best route depends on the location of the indoor and outdoor units.
Vertical trunking can often look particularly neat when it follows a natural line down the building.
Horizontal routes can also work well when aligned with architectural features such as:
- Window lines
- Brick courses
- Roof lines
- Cladding
- Existing services
A good installer will usually consider how the route looks as well as how it functions.
Use The Building To Make Trunking Less Noticeable
The existing features of a property can help make trunking more discreet.
For example, a route may be positioned:
- Beside a downpipe
- Near the corner of a building
- Along a window line
- Under an architectural ledge
- Along existing service routes
The aim is not necessarily to make trunking invisible, but to position it so it does not dominate the wall.
White Or Black Trunking?
The best colour depends on the property.
White Trunking
White trunking can work particularly well with:
- White render
- Light walls
- White windows
- Light coloured cladding
Black Trunking
Black trunking can work particularly well with:
- Black window frames
- Dark cladding
- Dark brickwork
- Modern extensions
- Black gutters and downpipes
Choosing the right colour can make a surprisingly large difference to the overall appearance.
Can Air Conditioning Trunking Be Painted?
Some property owners may want the trunking to match a particular wall colour.
Whether trunking can be painted depends on the material and manufacturer guidance.
In many cases, choosing the most suitable available colour from the start is simpler.
If painting is important, check the product information first and use a suitable coating for the material.
What Size Trunking Should You Use?
Trunking needs to be large enough to contain all of the services running inside it.
This may include:
- Two insulated refrigeration pipes
- Electrical cable
- Communication cable
- Condensate drainage
A smaller trunking can look more discreet, but choosing one that is too small can make the installation difficult and untidy.
CoolEasy offers options including 72mm, 80mm and 100mm trunking.
Read our Air Conditioning Trunking Buyer’s Guide for help choosing the correct size.
Can You Hide Condensate Drainage In The Same Trunking?
Often, yes.
The condensate drain from the indoor unit may follow the same route as the refrigeration pipes and cables.
Running these services together can produce a much cleaner installation.
However, condensate still needs to drain correctly.
If gravity drainage is being used, the drain needs an appropriate downward route.
If this is not possible, a condensate pump may be required.
Read our Condensate Pump Buyer’s Guide for more information.
Can A Condensate Pump Be Hidden?
Some compact condensate pumps can be positioned discreetly close to the indoor unit or incorporated into a suitable trunking arrangement.
The exact installation depends on the pump design and available space.
However, appearance should not come before accessibility.
The pump may require inspection or maintenance in the future, so it should not be permanently concealed somewhere that cannot be reached.
Can Pipework Be Hidden Inside The Wall?
In some projects, services may be concealed within the building fabric.
This can create a very clean finish, but it requires considerably more planning.
Considerations include:
- Building construction
- Access to pipework
- Future maintenance
- Drainage
- Insulation
- Installation during renovation work
Concealed services are easier to plan during a renovation or new build than after a room has already been finished.
Hiding Pipework During A Renovation
If you are renovating a home and plan to install air conditioning, consider the system before walls and ceilings are finished.
This may allow pipe routes to be incorporated into the project more discreetly.
Speak to the air conditioning installer about:
- Indoor unit positions
- Outdoor unit positions
- Pipe routes
- Electrical supplies
- Condensate drainage
- Future access
Planning early can make the finished system much less noticeable.
Hiding Pipework In A Finished Home
You do not need to be carrying out a full renovation to achieve a neat installation.
In an existing property, trunking can cover services without major building work.
A good installation can often use:
- A carefully positioned indoor unit
- A direct wall exit
- A short external trunking run
- A discreet outdoor condenser position
- Trunking that matches the property
This can produce a very tidy result with relatively little disruption.
Hiding Pipework For Multi Split Air Conditioning
Multi split systems require more planning because several indoor units connect to the outdoor system.
This can mean several separate pipe runs around the property.
To keep the installation tidy:
- Plan all indoor unit positions together
- Look for shared service routes where appropriate
- Keep pipe runs organised
- Use trunking consistently
- Choose suitable trunking sizes
- Avoid unnecessary crossing routes
The earlier the complete installation is planned, the easier it is to make a multi room system look discreet.
How To Hide Air Conditioning Pipework In A Bedroom
Bedrooms are one area where customers are often particularly concerned about appearance.
For the neatest result, consider positioning the indoor unit on or close to an external wall.
This may allow:
- Minimal visible internal pipework
- A direct wall exit
- External trunking rather than internal trunking
- A short service route
The unit position still needs to provide effective airflow and comfortable operation.
How To Hide Pipework In A Living Room
Appearance can be particularly important in living rooms.
Consider:
- Positioning the indoor unit on an external wall
- Keeping the wall exit close to the unit
- Using trunking that matches the décor
- Planning routes around architectural features
- Avoiding long visible runs where possible
A little planning before installation can dramatically improve the finished appearance.
Can You Hide The Outdoor Unit Too?
The outdoor condenser can sometimes be positioned somewhere less prominent, such as the side of the property rather than directly beside a patio or seating area.
However, you should not tightly conceal or box in an outdoor air conditioning unit.
It needs sufficient airflow to operate properly.
Avoid:
- Tightly enclosed decorative boxes
- Dense planting immediately around the unit
- Solid screens positioned too close
- Storage placed in front of the condenser
A discreet location is usually better than trying to physically hide the unit.
Keep Future Maintenance In Mind
It can be tempting to hide every part of an installation completely.
However, the system may need servicing or repairs later.
Make sure:
- The indoor unit remains accessible
- The outdoor unit can be serviced
- Trunking covers can be removed where necessary
- Condensate pumps remain accessible
- Drainage can be inspected
A good installation combines appearance with practical access.
Common Pipework Appearance Mistakes
If you want a discreet air conditioning installation, avoid these common mistakes:
- Choosing indoor and outdoor unit positions independently
- Leaving the pipe route until installation day
- Using trunking that is too small
- Forgetting trunking corner pieces
- Using a colour that clashes with the property
- Creating unnecessary bends
- Running services diagonally across walls
- Ignoring condensate drainage
- Trying to completely hide components that need maintenance access
- Boxing in the outdoor condenser and restricting airflow
Planning A Neat Air Conditioning Installation
Before installation, work through these points with your installer:
- Where will the indoor unit go?
- Can it be positioned on an external wall?
- Where will the services exit the building?
- Where will the outdoor unit go?
- What is the shortest practical pipe route?
- Where will trunking be visible?
- Would white or black trunking look better?
- What trunking size is needed?
- How many corners and fittings are required?
- Where will condensate drain?
- Will a condensate pump be needed?
- Can all components still be accessed for servicing?
Air Conditioning Trunking Options
CoolEasy stocks air conditioning installation accessories for creating neat domestic and commercial installations.
White Trunking
White trunking is a popular choice for light coloured homes, render and white window frames.
Black Trunking
Black trunking can complement dark windows, modern extensions, cladding and darker external finishes.
Different Trunking Sizes
The correct trunking size depends on the amount of pipework, insulation, drainage and cable being concealed.
Browse our installation accessories or read our Air Conditioning Trunking Buyer’s Guide.
Air Conditioning Pipework FAQs
Can air conditioning pipework be hidden?
Yes. Purpose designed trunking can cover visible refrigeration pipes, electrical cable and condensate drainage.
Does AC pipework have to be visible inside the room?
Not necessarily. If the indoor unit is positioned on an external wall, the services can often pass through the wall close to the unit, leaving little visible pipework indoors.
Can air conditioning pipework go inside walls?
It can be concealed in some installations, particularly during renovation or construction work, but future access and installation requirements need to be considered.
Can AC pipes run through a loft?
Some installations may use loft or ceiling spaces as part of the pipe route, provided the route is suitable for the system and installed correctly.
Can air conditioning trunking be used indoors?
Yes. Trunking can conceal pipework inside a room where the services cannot pass directly through an external wall.
Can air conditioning trunking be used outdoors?
Yes. Suitable trunking is commonly used on external walls to protect and conceal the service route between indoor and outdoor units.
Can condensate drainage go inside trunking?
Yes, provided the trunking has enough room and the drain can maintain the correct route. Gravity drainage requires an appropriate downward fall.
What colour trunking should I choose?
Choose a colour that complements the building. White often suits light walls, while black can work well with dark windows, cladding and modern exterior details.
What size trunking do I need?
The size depends on the refrigeration pipes, insulation, electrical cable and drainage that need to fit inside. Your installer should confirm the appropriate size.
Can I hide an outdoor AC unit inside a box?
You should not tightly enclose the condenser because it needs adequate airflow. A less visible installation location is usually a better solution.
When should the pipe route be planned?
Ideally before the air conditioning system is installed. Planning the indoor unit, outdoor unit, drainage and trunking together generally produces the cleanest result.
Final Advice: Plan The Pipework Before The Installation Starts
Air conditioning pipework does not have to spoil the appearance of your home or commercial property.
Purpose designed trunking can conceal refrigeration pipes, cables and condensate drainage while protecting the services and creating a much cleaner finished installation.
The biggest difference comes from planning. Choose the indoor and outdoor unit positions together, keep the pipe route as simple as possible, select suitable trunking and think about drainage before installation begins.
A few decisions made before the installer starts work can make the final air conditioning system far less noticeable.
Browse our air conditioning installation accessories, read our Air Conditioning Trunking Buyer’s Guide, or speak to the CoolEasy team if you need help planning your installation.